Inflatable knee bolsters have been developed to enhance vehicle occupant protection in the event of sudden vehicle deceleration. Such devices increase the duration of deceleration of occupants' femurs and control upper torso kinematics during a frontal impact event. The bolster impact surface is moved from a stored position to an extended position to intercept an occupant's knees early in the impact event. This allows the knees more time to decelerate to the vehicle's final velocity. The initial positioning of the bolster impact surface in a retracted, stored position allows more styling flexibility and enhances occupant ingress and egress.
Typical inflatable knee bolster installations comprise an inflatable air bag sandwiched between an impact surface and a reaction surface. When the inflator is triggered, the air bag expands to move the impact surface a predetermined distance to active position. This position may be determined by tethers between the reaction and impact surfaces. These installations comprise numerous parts, bits and pieces and require careful installation.
It would be desirable to provide a simpler inflatable knee inflatable bolster which would be less costly to manufacture and assemble into the vehicle. To this end it is believed to be advantageous to utilize bolster configurations which utilize a relatively small number of components which may be easily assembled and which exhibit effective deployment in an operational situation.